摘要:

ABSTRACTThe dynamic viscoelastic properties of five mayonnaise products were evaluated at 5–30C and 0,031‐31,4 s−1. The composition of the products was held constant, while the type of egg product was varied. Two egg yolks (native and spraydried) and three whole egg products (native, dried‐yolk containing and low‐in‐cholesterol‐yolk containing) were used as the emulsifiers. Temperature generally produces a decrease in the viscoelastic functions. A replacement of yolk (native or not) by egg white reduces the viscoelastic properties of mayonnaise. Processed yolk gives rise to greater viscoelastic parameters than native yolk. This effect loses significance when yolk is diluted by native egg white. The low‐cholesterol mayonnaise has similar viscoelastic properties when compared to commer

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe texture profile of canned peach fruits was studied using magnitude estimation as a scaling method. Their sensory characteristics were assessed using as a modulus either a model fruit or a real fruit sample. The sequence of appearance of the textural characteristics was determined during 4 stages of assessment (nonoral, first bite, during mastication, after effects). Four different varieties of peach fruits were canned and the effect of four processing variables (level of heat treatment, degree of ripeness, sugar concentration in the processing liquid and hardness of the processing liquid) on the texture profile of the fruits was examined. The results showed that an increase in the severity of the heat treatment and the degree of ripeness of the fruit resulted in a decrease in the firmness, crunchiness and chewiness of the canned fruit. Fibrousness was similarly affected but to a lesser extent. Freshness and juiciness were also negatively affected by these variables. An increase in the sugar concentration and hardness of the processing liquid resulted in an increase in the firmness, crunchiness and chewiness of the canned fruit. Fibrousness, freshness and juiciness were similarly affected but to a lesser extent.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTPublished sigmoid relationships between sensory crunchiness/crispness scores of five breakfast cereals and water activity (Sauvageot and Blond 1991) were fitted with the model Y(aw) = Yo/{1 + exp [aw‐ awc)/b]}, where Y(aw) is the sensory score at a given awlevel, Yothe score of the cereal at the dry (glassy) state, awca critical water activity representing the inflection point of Y(aw) and b a constant representing the steepness of Y(aw) in the awregion where much of the plasticization occurs. In all five cases the fit of the model, which had previously been used with instrumental mechanical parameters of stiffness and crunchiness, was almost perfect (r2in the range of 0.997–0.999). All the cereals had similar Yoand awcvalues, Yobetween 7.5 and 7.9, on a scale of 10, and awcbetween 0.62 and 0.68. The range of water activity in which most of the perceived crunchiness/crispness loss took place, however, varied considerably among the five cereals, with the constant b being in the range of 0.046–0.093. Since according to this model about 90% of the perceived crunchiness/crispness loss occurs within awc± 3b these numbers correspond to water activity spans between about 0.28 and 0.55, respec

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00770.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTDynamic viscoelastic parameters and chemical properties of Mozzarella cheese produced using a “no‐brine” cheese making method with 3 different cooking temperatures (38, 41, and 44C) were determined. Samples were stored for 3 weeks at 4C before dynamic mechanical analysis at 22C. G', G” and tan δ were 5.8 – 6.4 × 105dyne/cm2, 1.9 – 2.1 × 105dyne/cm2, and 0.33 – 0.35, respectively, at 1% strain and 10 rad/s. The percentage of intact αs‐casein and β‐casein were 38–40% and 33–35% of total protein in the cheese, respectively. The range of cooking temperatures used in this experiment had little effect on dynamic viscoelastic properties or the amount of int

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00771.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe vane method in controlled shear stress mode was used to determine the yield stress and the shear rate—shear stress data of tomato purees containing 10–35% pulp of two different average particle sizes: 0.34 and 0.71 mm. Consistency index and apparent viscosity increased significantly with pulp content and decreased with average particle size. The effect of pulp weight fraction (P) on relative viscosity (ηr) could be described by the single parameter equation: ηr= [1 – (P/A)]−2, while the effect of particle diameter on ηrcould be described using Peclet number. Magnitudes of yield stress determined directly by the vane method were higher than those obtained by using the Casson model, and were proportional to the square of pulp content. Reduced Casson yield stress—P data on purees of both particle sizes followd a single curve. Effects of pulp content and particle size on vane yield stress and apparent viscosity were evident from the correlation forms with high

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe rheological properties of linseed polysaccharide gels in the presence of citric acid, calcium and magnesium carbonates were studied using a factorial design and the Herschel‐Bulkley model. The yield stress and consistency index increased with the concentration of calcium and magnesium ions, while the flow behaviour index decreased, imparting stability to the gel. With citric acid, s̀oand k reached a maxima and then decreased, while n increased after an initial dip. The effect of pH (3.4–9.3), sucrose (45–55%), and polysaccharide (0.6–0.8%) on rheological constants were modelled using polynomials where up to fifth power of pH was required. Ln(s̀o), ln(k), and n were fitted to the standardised (normalised) forms of pH, In (sucrose) and In (polysaccharide) with multiple correlations of 0.95, 0.97 and 0.98, respectively. The two optima (with pH) were computed using Nelder and Mead's flexible polyhedral search method. Both required 55% sucrose and 0.8% polysaccharide with pH of 4.3 and 7.3, respectively. The models at the two optima are discussed through 3‐D graphs. The technological implications of the dual optima have been indicated. This is, probably, the first report where two optima, with pH, have been observed for a gel forming pol

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTElectromyography was used as a noninvasive and unobtrusive technique to characterise chewing patterns for a range of foods. Differences between subjects for a variety of aspects of chewing sequence are recorded for a range of foods (carrot, apple, roast pork, salami, biscuit and toast). Identifiable subgroups of subjects differing in chewing behaviour existed within the random sample of 52 dentate subjects. The five subgroups accounted for 52%, 21%, 11%, 10% and 6% of the sample population. Major discriminating factors between the behavioural groups lie in their chewing time and the muscle work rate during chewing. Sensory ratings for firmness and rubberiness of model foods differed significantly between the subjects exhibiting different chewing behaviours. Chewing behaviour may influence consumers’ perceptions about the texture of a foo

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe effect of particle size on the cooking behaviour of rice (Oryzae sativa, sub sp. Indica kato) flour was studied with the Brabender Viscoamylograph. Among the flours of different average particle sizes (307, 214, 165, 138, 114, 90 and 71 μ) studied, flours of 138 and 165 μ showed high breakdown ratios of 0.984 and 0.866 and set back ratios of 2.333 and 2.143, respectively. Comparatively, for vermicelli making, the flours of 138 and 165 μ yielded a product with better scores for textural profile, highlighting the importance of particle size of flours in the preparation of rice based vermicel

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

GENERAL PRINCIPLES: Dynamic Rheological Properties and Microstructure of Partially Insolubilized Whey Protein Concentrate Gels.T.Y. Hung and D.M. SmithGENERAL PRINCIPLES: Stress Relaxation of Fruit Gels. Evaluation of Models and Effects of Composition.M. Gamero, S.M. Fiszman and L. DuranINSTRUMENTATION&METHODOLOGY: Physicochemical and Sensory Characteristics of Selected Michigan Sweet Cherry (Prunus aviurnL.) Cultivars.D.E. Guyer, N.K. Sinha, T‐S Chang and J. N. CashINSTRUMENTATION&METHODOLOGY: Measuring Tenderness of Meat Products by Warner Bratzler Shear Press.M. Zhang and G.S. MittalINSTRUMENTATION&METHODOLOGY: A Filament Stretching Device for Measurement of Extensional Viscosity.V. Tirtaatmadja and T. SridharINSTRUMENTATION&METHODOLOGY: Fractal Analysis to Characterize Ruggedness Changes in Tapped Agglomerated Food Powders.B.J. Berletta and G.V. Barbosa‐CanovasINSTRUMENTATION&METHODOLOGY: Performance of the Helical Screw Rheometer for Fluid Food Suspensions.M.S. Tamura, C.F. Shoemaker and J.M. HendersonINSTRUMENTATION&METHODOLOGY: Objective Measurement of Retrogradation in Cooked Rice During Storage.I. Lima and R.P. SinghINSTRUMENTATION&METHODOLOGY: Compressive Stress‐Strain Relationships of Two Puffed Cereals in Bulk.C. Nuebel and M. PelegINSTRUMENTATION&METHODOLOGY: Effects of Flour‐to‐Water Ratio and Time of Testing on Sorghum Porridge Firmness as Determined by a Uniaxial Compression Test.A.A. Mohamed, B.R. Hamaker and A. AboubacarINSTRUMENTATION&METHODOLOGY: Relationships Between Electromyography, Sensory and Instrumental Measures of Cheddar Cheese Texture.F.R. Jack, J.R. Piggott and A. PatersonSENSORY ASSESSMENT: What Sensory Characteristics Drive Product Quality? An Assessment of Individual Differences.H. Moskowitz and B. KriegerSENSORY ASSESSMENT: Time‐Intensity Methodology for Beef Tenderness Perception.L. M. Duizer, E.A. Gullett and C.J. FindlayFACTORS AFFECTING TEXTURE: Hydrothermal Processing of Pacific Chum Salmon: Effects on Texture and In‐Vitro Digestibility.S. Bhattacharya, G.S. Choudhury and S. StudenakerFACTORS AFFECTING TEXTURE: Rheological Properties of Mozzarella Cheese Filled with Dairy, Egg, Soy Proteins, and Gelatin.Y.L. Hsieh, J.J. Yun and M.A. RaoFACTORS AFFECTING TEXTURE: Firmness of Canned Grapefruit Sections Improved with Calcium Lactate.T.A. BakerFACTORS AFFECTING TEXTURE: Mass Transfer and Textural Changes during Processing of Apples by Combined Methods.A. Monsalve‐Gonzalez, G.V. Barbosa‐Canovas

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY